First Indian Navigation Satellite boosted to Orbit by PSLV

July 1, 2013

Photo: Indian Space Research Organization

India has successfully put the country’s first Navigation Satellite into orbit on Monday. A Polar Satellite Launch Vehicle blasted off from the Satish Dhawan Space Center on India’s East coast at 18:11 UTC and made a flawless ascent mission delivering the IRNSS-1A spacecraft to its intended orbit about 20 minutes after launch. The flight was declared a complete success – marking the birth of India’s own navigation constellation, the Indian Regional Navigation System that will cover the country and surrounding areas.

Monday’s launch was preceded by a 64-hour 30-minute countdown sequence that began on Saturday and featured the final preparatory steps to prepare the PSLV for its flight. Countdown operations officially commenced at 7:11 local time on June 29.

During the countdown, the second and fourth stage of the launch vehicle were loaded with propellants. The first and third stage are both solid-fueled and loaded prior to launch vehicle integration. In addition, the roll reaction control system on the PS1 first stage was loaded with propellants on Saturday. Fueling was completed without any problems.

As part of countdown operations, the final tests were completed on the launch vehicle and its payloads. On Monday, the Mobile Service Tower was retracted, first to a stand-off distance of 50 meters before rolling to its launch position, 160 meters from the rocket that was fully fueled at this point. Afterwards, teams made final close-outs on PSLV and the service structure before departing the launch complex for the final countdown sequence.

As part of the final countdown sequence, the flight computers of PSLV were configured for flight and received their appropriate flight software. Also, the IRNSS satellite was switched to battery power and transitioned to flight mode. As clocks ticked down, the PSLV also transitioned to internal power, pressurized its propellant tanks and assumed control of the countdown shortly before T-0.

As clocks hit zero at 18:11 UTC – 23:41 local, the large Core Stage and four of the six Solid Rocket Motors ignited - providing the kick the vehicle needed to jump off its launch pad and begin its ascent. In its XL configuration, the PSLV flies with six stretched Solid Rocket Boosters to provide an initial boost to the vehicle that also carries a full fuel load. At blastoff, the Rocket had a total thrust of 700,600 Kilograms for an initial thrust-to-weight ratio of 2.2.

As part of its rapid initial ascent, PSLV pitched over to start an easterly track before swinging south-east later in the flight to cross the Bay of Bengal. 25 seconds into the flight, the two-remaining boosters of the vehicle ignited, bringing the total thrust up to 803,000 Kilograms.

PSLV quickly gained altitude and started racing downrange as the six boosters burned. Each of the XL Boosters is 13.5 meters long, 1 meter in diameter and has a liftoff mass of 14,000 Kilograms. The first four Boosters burned out at T+50 seconds. The launcher held onto the four boosters until T+1 minute and 10 seconds. At that time, the four boosters were separated in pairs, just 0.1 seconds apart. The remaining two boosters completed their burn and separated at T+1:32. At that point, the vehicle was already flying 39 Kilometers high with a velocity of 1,955 meters per second.

Powered ascent continued on the PS1 stage alone. The PS1 stage of the launcher has a liftoff mass of 168,200kg being 2.8 meters in diameter and 20.34 meters long. It consists of five segments that are loaded with solid HTPB-based propellant. Vehicle control is provided via Secondary Injection Thrust Vector Control for pitch & yaw and two thrusters for roll. Overall, PS1 provides a thrust of 495,600 Kilograms.

Burnout and separation of the first stage took place at T+1 minute and 55 seconds, followed by Stage 2 ignition an instant later. The second stage of the launcher assumed control of the vehicle at 58 Kilometers in altitude.

*File Image* - Photo: Indian Space Research Organization

The second stage of the PSLV launcher is powered by a 799-Kilonewton Vikas engine that consumes Unsymmetrical Dimethylhydrazine and Nitrogen Tetroxide. The second stage is 12.8 meters long and has a liftoff mass of 46,000kg. It powered the vehicle for 2 minutes and 32 seconds.

At T+3 minutes and 29 seconds, the vehicle passed 113 Kilometers in altitude, making it safe to jettison the protective payload fairing as aerodynamics could no longer harm the satellite. PSLV’s fairing is 3.2 meters in diameter and 8.3 meters long.

*File Image* - Photo: Indian Space Research Organization

4 minutes and 27 seconds into the mission, the second stage shut down after completing its burn. After a 1-second delay, the solid rocket motor of the PS3 stage was ignited. The third stage has a reduced diameter of 2.02 meters. It is 3.54 meters long and has a launch mass of 7,800kg. Vehicle control was provided by the fourth stage attitude control system. The third stage provides a thrust of 24,880 Kilograms over a 112-second burn.

After the burn was complete, the launch vehicle began a short coast phase during which it held onto the third stage. Third stage separation occurred at T+8:41 at an altitude of 163 Kilometers while the vehicle was moving at 7,760m/s.

Following staging, the vehicle continued its coast, maintaining attitude by using the attitude control system of the fourth stage. At T+11:16, the two L-2-5 engines of the fourth stage ignited on a 8-minute 32-second burn to boost the stack into a Geosynchronous Transfer Orbit. PSLV’s Upper Stage is powered by two L-2-5 engines providing a total thrust of 1,500 Kilograms. The engines use Monomethylhydrazine and Mixed Oxides of Nitrogen as propellants. The stage is 2.6 meters long, 2.02m in diameter and has a liftoff mass of 2,520kg.

Fourth stage cutoff occurred 19 minutes and 48 seconds after liftoff. After shutdown, the Reaction Control System of the fourth stage re-oriented the vehicle for spacecraft separation.

At T+20 minutes, the IRNSS-1A spacecraft was separated – being sent into a 283 by 20,630-Kilometer Orbit at an inclination of 17.9 degrees (Target: 284 by 20,650 Kilometers, 17.86 degrees. Spacecraft separation occurred at an altitude of 500 Kilometers.

This flight marked the 24th PSLV flight since its inauguration in 1993 and the second Indian space mission of 2013, both were successes. One more PSLV flight is planed for this year – the launch of the Indian MangalYaan Mars Orbiter planned for October 22. India’s Geosynchronous Satellite Launch Vehicle will also return to flight this year. GSLV-D5 is penciled in for early August.

With Monday’s mission being a full success, India has taken the first step to bringing its very own Navigation Satellite Constellation on-line.

About IRNSS-1A

The IRNSS project was approved in 2006 and is baselined for a total of seven satellites. In its fully operational configuration, the IRNSS constellation will consist of three satellites in Geostationary Orbit and four spacecraft in Geosynchronous Orbit inclined 29 degrees to the equatorial plane. The system is designed to be compatible with the US Global Positioning System and Europe's upcoming Galileo constellation using navigation signals in S-Band and at L5. The deployed constellation will only cover India and surrounding regions.

The IRNSS-1A satellite has been designed and developed by the Indian Space Research Organization, ISRO. It is based on the I-1K Satellite Bus. The Spacecraft Bus is 1.58 by 1.5 by 1.5 meters in size with a dry mass of 614 Kilograms. Fully fueled, the spacecraft weighs 1,425kg.

The satellite features two deployable solar panels that are equipped with Ultra Triple Junction solar cells that generate a total power of 1,660 Watts. Power storage is accomplished with a single 90 Amp-hour battery, an avionics system controls power distribution and battery charging.

Image: Indian Space Research Organisation

The satellite platform is three-axis stabilized using a zero momentum system consisting of reaction wheels, magnetic torquers as well as attitude control thrusters. A total of 12 thrusters are mounted on the vehicle. Navigation data is acquired by Sun and Star Trackers as well as an inertial measurement unit. The satellite provides precise pointing capability.

Photo: Indian Space Research Organisation

The main propulsion system for large orbit adjustments and apogee maneuvers consists of a Liquid Apogee Motor, LAM. It provides a thrust of 440 Newtons and uses Mixed Oxides of Nitrogen as fuel and Unsymmetrical Dimethylhydrazine as oxidizer. The engine operates and an mixture ratio (O/F) of 1.65 and has a nozzle ratio of 160. The engine’s injector is a co-axial swirl element made of titanium while the thrust chamber is constructed of Columbium alloy that is radiatively cooled. The engine is certified for long firings of up to 3,000 seconds. The Propellants are stored in spherical tanks that are pressurized with Helium.

The twelve 22-Newton attitude control thrusters are connected to the same propellant system and also feature the basic design with a Titanium alloy injector and Columbium nozzle. The thrusters operate in blowdown mode at a chamber pressure of 0.68 Mpa. The thrusters have an area ratio of 100.

The heart of the satellite payload is a highly accurate Rubidium atom clock that is used to generate navigation signals. The payload of the satellite operates in L5-band (1176.45 MHz) and S-Band (2492.028 MHz). The Spacecraft will support Standard Positioning Service that is open to all users as well as Restrictive Service with high accuracy that is only provided to authorized users. The system will provide an accuracy of 10 to 20 meters.

Image: Indian Space Research Organisation

In addition to the navigation payload, the satellite is equipped with a ranging system that is used to precisely calculate the vehicle’s range. A C-band transponder is used to determine accurate range data. For even more precise data, the satellite carries Corner Cube Retro Reflectors that can be used for laser ranging that will yield extremely accurate data. Each IRNSS satellite has a life expectancy of 10 years. Once fully deployed, the IRNSS constellation will provide navigation service to India and surrounding areas as far as 1,500 Kilometers from the primary service zone that is enclosed by a rectangle of a latitude of 30 degrees south to 50 degrees north and longitude of 30 degrees east to 130 degrees east. The satellite constellation will be supported by a large ground segment of core operations centers as well as ranging and tracking stations positioned all across India.

The IRNSS Navigation System will serve a number of applications. It will be used for terrestrial, aerial and marine navigation, precise timing, mapping and geodetic data acquisition, disaster management and vehicle tracking and fleet management.

Approximate Ascent Ground Track

Image: Google Earth/Spaceflight101

India set to Launch its first Navigation Satellite via PSLV on Monday

June 28, 2013

India is set to launch the IRNSS Navigation satellite via its Polar Satellite Launch Vehicle on Monday from the country’s Satish Dhawan Launch Center. PSLV, flying in its XL configuration, is planned to blast off at 18:11 UTC on July 1, 2013. This launch will orbit the first satellite of the Indian Regional Navigational Satellite System (IRNSS) – a project that has been in the making for several years and suffered a number of delays as it was initially planned to be operational by the end of 2012.

Photo: Indian Space Research Organisation

The PSLV Launch Vehicle that will perform this flight stands fully assembled inside the Service Structure at the Satish Dhawan Space Center. The Launch Campaign at the Space Center began on April 15, 2013 when the PS1 solid-fueled first stage was moved to the Mobile Service Tower to be integrated on the launch table. PS1 has a loaded mass of 168,200 Kilograms being 2.8 meters in diameter and 20.34m long. In the XL configuration, the PSLV launcher uses six stretched Solid Rocket Boosters that were mated to PS1, one by one, over the course of several weeks. Each of the boosters has a launch mass of 14,000kg being 1m in diameter and 13.5m in length. Four boosters are ground-lit while the remaining two ignite in flight.

With the boosters in place, teams hoisted the PS2 second stage above the stack and carefully centered it onto the first stage. Unlike the first stage, the second stage of the PSLV is liquid fueled using storable propellants. It was a liftoff mass of 46,000kg and is 2.8 by 12.8 meters featuring a Vikas engine. Atop the second stage, the third stage was installed. It uses solid fuel and weighs 7,800kg being 3.54m long and 2.02m in diameter. Afterwards, the fourth stage was attached to the vehicle. It is a liquid-fueled stage equipped with two L-2-5 engines that use storable propellants. The small fourth stage is 2.02m in diameter and 2.6m long with a fueled mass of 2,920kg. In the XL config, the fourth stage is fully loaded for flight while it only uses a partial fuel load in the Core Alone version. With all four stages and boosters integrated, an extensive testing campaign was started. During electrical testing, a problem with a Thrust Vector Control Actuator on the second stage was found. The component was replaced, causing a two-week launch delay pushing the launch from mid to late June. Another delay followed and liftoff is now set for 18:11 UTC on July 1.

The IRNSS-1A satellite completed its final processing for launch at the Satish Dhawan Space Center. It underwent final testing and reconfigurations as well as hazardous processing, being filled with 811kg of Mixed Oxides of Nitrogen and Hydrazine propellants for use during its 10-year mission.

When checkouts and processing were complete, the IRNSS spacecraft was installed atop the launch vehicle on June 24. Once in place atop the fourth stage of the launch vehicle and in its flight configuration, the satellite was encapsulated in the protective payload fairing. The PSLV fairing is 3.2 meters in diameter and 8.3 meters long, offering space to accommodate a variety of payloads.

After payload installation, Global Vehicle Checks of the integrated stack got underway taking three days to complete. On June 27, the launch team put the launcher and payload through a full countdown and launch rehearsal. Pre-launch operations were complete by June 28, to get the vehicle ready to begin the countdown on June 29.

The 64-hour 30-minute countdown sequence will prepare the stacked vehicle for flight. Nominal Countdown operations include the Propellant Loading of the second and fourth stage of the PSLV Launcher. Stages one and three are both solid-fueled. Also during the countdown, extensive checks of the rocket and the spacecraft are conducted as well as battery. In addition to that, India’s Ground Network of Tracking Stations is being configured for the flight.

More information on the IRNSS payload and the C22 flight profile is available below.